Field of the Invention
The present invention generally relates to video processing, and, more specifically, to a technique for reducing the power consumption of a video encoder engine.
Description of the Related Art
A conventional digital camera is typically configured to capture raw video data, process that raw video data, and then encode the processed video data according to a compression standard for storage purposes. An encoder engine within the digital camera typically is a fixed-function hardware unit that is responsible for encoding the processed video data and is usually programmed to implement a particular compression standard. For example, a Moving Picture Experts Group (MPEG) encoder engine could be responsible for encoding processed video data into an H.264 compressed format.
The rate at which the processed video data is made available to the encoder engine may vary over time according to the frame rate at which the raw video data is captured, the resolution of that raw video data, and/or a color format associated with the raw video data, among other factors. These latency variations may be partially absorbed by temporarily storing the processed video data in a buffer that is accessible by the encoder engine. However, the encoder engine must consume the processed video data from the buffer with sufficient speed so that the buffer does not overflow. Consequently, the clock frequency of the encoder engine is typically pre-set to the maximum frequency that is needed to prevent buffer overflow.
One drawback of this approach is that the encoder engine may operate with the pre-set maximum frequency even in situations where the processed video data is pushed into the buffer at a very low rate. In these situations, the encoder engine may be idle across many cycles, thereby wasting power. Further, maintaining the aforementioned maximum clock frequency may require the core power of the conventional digital camera to be increased simply to support the operation of the encoder engine. In such situations, the core power may be increased even when none of the other components within the conventional digital camera requires such a power increase, thereby wasting additional power.
Accordingly, what is needed in the art is a more power-efficient encoder engine.